Pressure control valve

ABSTRACT

A pressure control valve in which the mass to be moved by the diaphragm is reduced by providing that a valve seat body having a valve seat face is placed in a middle region of the diaphragm. When the valve seat face lifts away from the valve closing body, fuel to be diverted flows from the pressure control side of the diaphragm to the return side of the diaphragm, via the valve seat face and a return conduit The pressure control valve is especially suitable for use in fuel supply systems of internal combustion engines.

BACKGROUND OF THE INVENTION

The invention is based on a pressure control valve for an internalcombustion engine. A pressure control valve is already known (U.S. Pat.No. 5,078,167) that is disposed on a fuel filter of a fuel supply systemfor an internal combustion engine and that has a base body in the middleregion of which a tubular valve seat body with a valve seat face issecured. Between the base body and the valve seat body, a diaphragm isfastened firmly into the middle region, its periphery being fastened toa flange of the base body. A fuel inlet neck protrudes with great playinto the valve seat body and is connected to the pressure side of thefuel feed pump. Some of the fuel flowing via the fuel inlet neck reachesthe valve seat body and from there passes through the filter cloth ofthe fuel filter and after that, via an opening in the base body, acts ona pressure control side of the diaphragm. Connected to the return sideof the diaphragm, remote from the pressure control side of thediaphragm, is a valve closing body, which in sealed fashion surroundsthe fuel inlet neck and is displaced on the diaphragm by a motion of thediaphragm, so as to be lifted more or less away from the valve seat faceof the valve seat body, counter to the force of a compression springengaging the return side of the diaphragm. Such a pressure control valveis very complicated in design and because of the friction resulting fromthe sealing of the valve closing body on the fuel inlet neck, there isundesirable hysteresis and imprecision of control. Moreover, the valveclosing body has a very large mass, which must be moved by the diaphragmfastened in its middle region and on its periphery firmly to the basebody, and as a result the reaction speed of the pressure control valveto pressure changes is also impaired.

A pressure control valve is also known (U.S. Pat. 4,300,510) that isdisposed on a fuel distributor line. A diaphragm of the pressure controlvalve is fastened on its periphery between an annular flange and the capand in its middle region supports a valve closing body, which cooperateswith a flat valve seat face on a valve seat body protruding into thefuel distributor line. A compression spring is supported on the side ofthe diaphragm remote from the valve seat body and on its other end restson the cap. The pressure of the engine prevailing in the air intake linealso acts on the side of the diaphragm remote from the valve seat body.Such a pressure control valve has the disadvantage that the masses thatmust be moved by the diaphragm are still relatively great, so that thereaction speed in the event of pressure changes is still too slow.

ADVANTAGES OF THE INVENTION

A pressure control valve of the invention, has the advantage over theprior art that it can be made in a simple way without major effort orexpense, is compact in structure precisely controls the predeterminedpressure, and reacts more quickly to pressure changes. The pressurecontrol valve of the invention is also especially well-suited forcontrolling pressure in so-called "returnless" fuel injection systems,in which the excess fuel, pumped by the fuel pump and not injectedthrough the injection valves, is returned to the fuel tank directlydownstream of the fuel pump via the pressure control valve. Routing thereturn conduit through the diaphragm leads to a reduction in the massesmoved and thus to an improvement in the reaction speed of the pressurecontrol valve. The axial flow has advantages from the installationstandpoint and enables better integration with other units.

Advantageous further features of and improvements to the pressurecontrol valve are possible with the provisions recited.

As the valve closing body, it is especially advantageous to use a ball,which as is known can be made with high precision. It is alsoadvantageous to flatten this ball so that it has a flat sealing face,which cooperates with a flat valve seat face that is moved by thediaphragm.

It is advantageous to embody the base body as a cup-shaped sheet-metalbody with a bottom, and to form retaining tongues out of the bottom thatare bent into the interior of the base body and partially surround thevalve closing body for bearing purposes in such a way that it isrotatable.

It is also advantageous to provide a valve seat body in the middleregion of the diaphragm that has the valve seat face and a returnconduit leading from it to the return side.

It is additionally advantageous that the force of a restoring springengaging the return side of the diaphragm is brought to bear by bendingthe bottom of the base body or of some body on which the end remote fromthe diaphragm of the restoring spring rests.

It is especially advantageous to embody the diaphragm resiliently from ametal and to provide it directly with the valve seat face and a returnconduit leading to the return side; as a result, the expense forproducing the pressure control valve and the masses to be moved can bothbe reduced especially sharply.

To reduce the influence of the compression force of the fuel flowing outthrough the return conduit on the diaphragm, it is advantageous to joina thin-walled tube in sealed fashion to the valve seat body on thereturn side of the diaphragm; this tube communicates for instance with ajet pump disposed in the fuel tank, on the intake side of a fuel feedpump.

It is also advantageous if a restoring spring in the form of a tensionspring engages the diaphragm, the spring being embodied as a helicalspring or a leaf-spring-like tension spring.

Another advantageous embodiment has the base body embodied as acup-shaped plastic body with a bottom on which the valve closing body issupported or on which the valve closing body is embodied in integratedfashion.

It is likewise advantageous to provide a sleevelike valve closing bodyon the base body, with a sealing face toward the diaphragm and a sleevebottom remote from the diaphragm, and to secure one end of a tensionspring, acting as a restoring spring, to the diaphragm and the other endof the tension spring to the sleeve bottom of the sleevelike valveclosing body.

It is also advantageous to fasten the diaphragm at its periphery to thebase body of plastic by means of a tubular intermediate part of plastic,and to have a cup-shaped plastic cap part to engage the intermediatepart, the cap part being axially movable relative to and fixible on theintermediate part.

It is also advantageous to join a valve seat body, which has the valveseat face and a return conduit leading from it to the return side, tothe diaphragm, in which the valve seat body includes a valve closingbody embodied as a ball disposed in a guide conduit located upstream ofthe valve seat face; on the return side of the diaphragm, a cap isjoined to the base body, on which cap a stop body pointing at the valveclosing body is disposed.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are shown in simplified form inthe drawing and described in further detail in the ensuing description.FIGS. 1-6 shows various arrangements of pressure control valves in fuelsupply systems of internal combustion engines; FIG. 7 shows a firstexemplary embodiment of a pressure control valve of the invention; FIG.8 is a section taken along the line VIII--VIII of FIG. 7; FIGS. 9-23show a second to a seventeenth exemplary embodiment of a pressurecontrol valve of the invention; FIGS. 24 and 25 show fragmentary viewsof the pressure control valve of FIG. 23; and FIGS. 26 and 27 shown aneighteenth and nineteenth exemplary embodiment of a pressure controlvalve according to the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In FIG. 1, reference numeral 1 indicates a fuel tank into which aso-called tank insert unit 2 is inserted, which is supplied with fuelfrom the fuel tank 1 via a compensation opening 3 in the wall of thetank insert unit. A fuel pump 4 is disposed in the tank insert unit 2and is driven for instance by an electric motor and furnishes fuel intoa fuel line 5 to outside the fuel tank 1 In the exemplary embodimentshown in FIG. 1, a fuel filter 7 is located outside the fuel tank 1 ortank insert unit 2 in the fuel line 5. The fuel line 5 discharges into aso-called fuel distributor 8, from whence the fuel reaches injectionvalves 9, which are inserted into the fuel distributor and four ofwhich, for instance, are shown. The injection valves 9 are inserted bytheir injection ends each into one individual intake tube of a cylinderof a mixture-compressing internal combustion engine 10 with externallysupplied ignition, and they inject fuel into the immediate vicinity ofthe inlet valves of the individual cylinders. Downstream of the fuelfilter 7, a branch line 12 that leads back to the tank insert unitbranches off from the fuel line 5. In the branch line 12, inside thetank insert unit 2, there is a pressure control valve 13, which keepsthe fuel pressure in the fuel line 5 upstream of the injection valves 9constant, and by way of which the excess fuel pumped by the fuel pump 4and not injected through the injection valves 9 is returned to the tankinsert unit 2. In the process, the fuel diverted by the pressure controlvalve 13 either passes from the housing of the pressure control valve 13into the tank insert unit 2 directly or flows into the tank insert unit2 via a return line 14 provided downstream of the pressure control valve13.

The exemplary embodiment of FIG. 2 differs from the exemplary embodimentof FIG. 1 only in that the pressure control valve 13 is located in thebranch line 12 outside the tank insert unit 2 and the fuel tank 1.

FIG. 3 shows an exemplary embodiment in which, while as in the exemplaryembodiment of FIG. 1 the pressure control valve 13 is located inside thetank insert unit 2, nevertheless the branch line 12 in this exemplaryembodiment of FIG. 3 already branches off from the fuel line 5immediately downstream of the fuel pump 4, inside the tank insert unit2. Such an embodiment, like that of FIG. 1 or 2 as well, is known as a"returnless" system, since here without long return lines, the excessfuel pumped by the fuel pump 4 and not injected through the injectionvalves 9 is returned to the fuel tank over the shortest possible path,or in other words without relatively long lines and hence also withoutundesired heating in the engine compartment. In the exemplaryembodiments of FIGS. 1 and 2 as well, it can still be said that a"returnless" system is involved, since in them the return flow of excessfuel takes place in the vicinity of the fuel tank 1.

FIG. 4 again shows an exemplary embodiment of a fuel supply systemembodied as a "returnless" system, in which the fuel filter 7 is alsodisposed directly downstream of the fuel pump 4, inside the tank insertunit 2, and the pressure control valve is mounted on the fuel filter 7or integrated with the fuel filter 7 and is also located inside the tankinsert unit 2, so that excess fuel is returned to the intake side of thefuel pump 4 again over the shortest path from the fuel line 5 inside thetank insert unit 2.

FIG. 5 shows an exemplary embodiment in which with the exemplaryembodiment of FIG. 1 as a point of departure, the excess fuel divertedinto the return line 14 by the pressure control valve 13 is notdelivered directly to the tank insert unit 2; instead, the return line14 terminates in a compensation opening 3, embodied as a jet pump, ofthe kind that is already well-known for filling such tank insert unitsor of the kind mounted on the intake side of fuel pumps. The returncourse shown in FIG. 5 of the return line 14 to the jet pump 3 can bedone correspondingly in the exemplary embodiments of FIGS. 2-4 as well.

As in the above exemplary embodiments, in FIG. 6 as well the elementsthat remain the same and function the same as those of the exemplaryembodiment of FIG. 1 are identified by the same reference numerals. InFIG. 6, the pressure control valve 13 is disposed downstream of the fueldistributor 8, preferably directly on the fuel distributor 8, and thereturn line 14 from the pressure control valve ends in the compensationopening 3, embodied as a jet pump, of the tank insert unit 2. FIGS. 1-6show only some of the possible arrangements of the pressure controlvalves described in the following drawing figures.

In FIG. 7, a first exemplary embodiment of a pressure control valve 13according to the invention is shown, which by way of example is disposedin a retaining body formed of a lower part 17 and an upper part 18. Thewords upper part and lower part are used here merely for the sake ofbetter distinguishing between the two parts. The upper part and lowerpart may be arbitrary elements of different units. The lower part 17 andupper part 18 enclose a receiving opening 19, extending into both parts,which is interrupted, at the plane dividing the two parts 17, 18, by afastening opening 20 of a larger diameter in at least one of the parts.An elastic seal 21 can for instance be provided in the dividing planebetween the lower part 17 and the upper part 18. In the lower part 17,the fuel line 5 leads into the receiving opening 19, while in the upperpart 18 the return line 14 leads away from the receiving opening 19. Thecarrier body formed of the parts 17, 18 may be embodied as a separatepart, but it may also be part of the fuel tank 1, the tank insert unit2, the fuel pump 4, the fuel filter 7, the fuel distributor 8, or someother unit of the fuel supply system. On installation of the pressurecontrol valve 13 inside the fuel tank 1 or tank insert unit 2, it ispossible for a closed upper part 18 to be dispensed with, since thediverted fuel can flow directly back from the pressure control valveinto the tank insert unit 2 or the fuel tank 1.

The pressure control valve 13 has a base body 24, embodied as acup-shaped, stepped sheet-metal body that has a bottom 25. Beginning atthe bottom 25, a bead 26 is formed on the circumference of the base body24; it defines a groove for a sealing ring 27 disposed on thecircumference of the base body. The sealing ring 27 rests sealingly notonly on the circumference of the base body 24 but also on the wall ofthe receiving opening 19 and thus divides the part of the receivingopening 19 communicating with the fuel line 5 from the part of thereceiving opening 19 communicating with the return line 14. At least tworetaining tongues 28 are formed out of the bottom 25 and bent into theinterior of the base body 24, where they form a kind of cage forsupporting a ball-like valve closing body 30. The valve closing bodyrests on the bottom 25, and the retaining tongues 28 are somewhat longerthan the radius of the valve closing body 30, which is embodied aslarger than a hemisphere, and with their free ends 33 they close animaginary circle that has a smaller diameter than the diameter of theball-like valve closing body 30 In any case, there is play between theretaining tongues 28 and the ball-like valve closing body, such that theball-like valve closing body can rotate freely between the retainingtongues 28 but cannot fall out of the cage formed by them. Aleaf-spring-like cocking spring 31 formed out of the plane of theretaining tongues and having four spring tongues 32, for instance, isdisposed between the bottom 25 of the base body 24 and the ball-likevalve closing body 30 and exerts a slight spring force on the valveclosing body 30, so that it is held at the free ends 33 in the retainingtongues 28, thus preventing the valve closing body 30, if jarring andshaking occur, for moving constantly relative to the retaining tongues28, which would cause undesired wear phenomena. The ball-like valveclosing body 30 is flattened and has a flat sealing face 34. After beingflattened, the ball-like valve closing body 30 is still larger than ahemisphere.

Remote from the bottom 25, the base body 24 has a collar 36, which isannular and on which a diaphragm 40, or a plurality of diaphragms 40placed one above the other, rests by its or their periphery. An annularshoulder 37 of a cup-shaped cap 38 rests on the circumference, on theside of the diaphragm 40 or diaphragms 40 opposite the collar 36. Acrimp edge 39 adjoining the collar 36 of the base body 24 is bent in a Uover the annular shoulder 37 of the cap 38 and exerts a fastening forcewith which the periphery of the diaphragm 40 or diaphragms 40 isfastened firmly between the collar 36 and the annular shoulder 37. Thediaphragm 40 is shaped in such a way, or has a material such, that it isresilient or elastic. The diaphragm 40 or diaphragms 40 may be formed ofrubber, a cloth with rubber coating, plastic, or metal in the form ofthin foils.

The pressure control valve 13 protrudes by its collar 36 or crimped edge39 into the fastening opening 20 between the lower part 17 and the upperpart 18 and is retained in it.

In its middle region, the diaphragm 40 has an aperture 42, through whicha cylindrical valve seat body 43 is thrust that has a flat valve seatface 44 toward the valve closing body 30. A counterpart disk 46 rests inthe middle region of the diaphragm, on a pressure control side 45 of thediaphragm 40 toward the valve closing body 30, and a spring plate 48rests in the middle region of the diaphragm, on a return side 47 of thediaphragm 40 toward the cap 38. The counterpart disk 46 and the springplate 48 also have apertures, aligned with the aperture 42 of thediaphragm 40, through which apertures the valve seat body 43 extends andprotrudes, with a radially extending deformation 49, past the springplate 48 and exerts a cocking force in the axial direction thatsealingly braces the valve seat body 43, the counterpart disk 46 and thespring plate 48 on the diaphragm 40 axially against one another. On theside toward the valve closing body 30, the valve seat body 43 protrudesradially with an annular edge past the counterpart disk 46.

The cap 38 has at least one outflow opening 51, which may be provided inthe cap bottom 52 and/or in the cylindrical jacket part of the cap. Arestoring spring 53 embodied as a compression spring is supported on thecap bottom 52; it likewise engages the spring plate 48 and thus urgesthe diaphragm 40 and the valve seat body 43 in the direction toward thevalve closing body 30. The spring force of the restoring spring 53,which determines the fuel pressure to be controlled, can be exerted byaxially pressing in on or pulling out the cap bottom 52 and/or thebottom 25 of the base body 24 in a central bearing region 62. If thepredetermined fuel pressure on the pressure control side 45 of thediaphragm 40 is exceeded, then the diaphragm 40 lifts the valve seatbody 43 away from the valve closing body 30, and fuel flows along thesealing face 34 and along the valve seat face 44 and from there, via areturn conduit 54 formed in the valve seat body 43, to the return side47 of the diaphragm and into the interior of the cap 38. As a result ofthe outflow openings 51 in the cap 38, the fuel can also flow directlyback into the tank 1 or tank insert unit 2, omitting the other part 18,if the pressure control valve 13 is built in there.

The forming of the retaining tongues 28 creates inlet openings 35 in thebottom 25 of the base body 24, by way of which openings the fuel,reaching the receiving opening 19 from the fuel line 5, flows into theinterior of the base body 24. The webs remaining in the bottom 25between the inlet openings 37 lend the central bearing region 62 of thebottom, in which the valve closing body 30 is supported, the capabilityof plastically deforming this central bearing region by exerting onlyslight forces.

FIG. 8 shows a plan view on the pressure control valve of FIG. 7, alongthe line VIII--VIII.

The valve seat body 43, the counterpart disk 46 and the spring plate 48may be made of metal, a suitable plastic, or some other material, suchas ceramic.

In the exemplary embodiments of pressure control valves according to theinvention, described in the following FIGS. 9-27, those elements of thepressure control valves that remain the same and function the same as inFIGS. 7 and 8 are identified by the same reference numerals. For theseidentical and identically functioning parts, reference is expressly madeto the description of FIGS. 7 and 8, so that this matter will not bedescribed again here. The exemplary embodiment of a pressure controlvalve shown in FIG. 9 differs from the pressure control valve of FIG. 7essentially only in that the valve closing body 30 is embodied as acomplete ball, or in other words without any flattening as the sealingface, and the valve seat face 44 on the valve closing body is likewisenot flat but instead is shaped conically or spherically. The valve seatbody 43 is provided integrally with a disk end 55 on its side resting onthe pressure control side 45 of the diaphragm, so that the counterpartdisk 46 provided in the pressure control valve of FIG. 7 is dispensedwith. Once again, the valve seat body 43 and the spring plate 48 maycomprise plastic, metal or some other material. On the bottom 25 of thebase body 24, at the transition to the cylindrical jacket region, detenttongues 57 are formed out and bent radially outward. From behind, thesedetent tongues 57 engage detent protrusions 58 of an annular disklikefilter body 59, across which a filter cloth 60 is spread, covering theinlet openings 35 outside the base body 24. This filter 59, 60 preventsparticles entrained in the fuel from reaching the region between thevalve closing body 30 and the valve seat face 44 and damaging thesefaces or from sticking there and thus impairing the function of thepressure control valve.

In the exemplary embodiment of FIG. 10, a filter 59, 60 is againprovided, whose detent protrusions 58 however extend through the inletopenings 35 and engage the bottom 25 of the base body 24 from behind onthe inside, so that no detent tongues 57 as in the exemplary embodimentof FIG. 9 are needed. Moreover, no cap is provided. In this exemplaryembodiment, the restoring spring 53 is embodied as a striplike orannular leaf spring, which is fastened on its circumference to thediaphragm 40 by the crimp edge 39 on the base body 24 and which extendsradially inward far enough that it engages the spring plate 48 anddefines a flow opening 61 for the fuel flowing out of the return conduit54. The use of a leaf spring as a restoring spring makes a very shortembodiment of the pressure control valve 13 in the axial directionpossible.

FIG. 11 shows the use of a thin, foil-like metal diaphragm 40, which isembodied as elastically resilient by means of additional corrugatedregions and is fastened at its periphery, with the interposition of aseal 63, to the collar 36 of the base body 24 by the crimped edge 39. Inits middle region, the diaphragm 40 is embodied as flat in order to formthe valve seat face 44, and it there has the return conduit 54 to thereturn side 47. The diaphragm 40 may, however, also be bent in theregion of the return conduit 54 toward the flat sealing face 34 of theball-like valve closing body 30, so that in a manner not shown, anannular valve seat face 44 is formed on the diaphragm 40. For controlpurposes, the only mass that must be moved is that of the diaphragm, andas a result a particularly fast speed of response to pressure changes isobtained. The diaphragm cooperates with a flat sealing face 34 of theball-like valve closing body 30 that is supported in a central bearingregion 62 of the bottom 25 of the base body 24 by a cup-shaped retainingsleeve 64, which reaches with retaining tongues 28 through inletopenings 35 provided in the bottom 25 and, in the manner described forFIG. 7, rotatably supports the valve closing body 30 by means of theretaining tongues. The retaining sleeve 64 rests with a constriction onthe outside of the bottom 25. A cocking spring 31 embodied as acompression spring between the bottom 25 and the valve closing body 30urges the valve closing body 30 toward the free ends 33 of the retainingtongues 28, and as a result the valve closing body 30 and the retainingsleeve 64 are pressed toward the diaphragm 40. The spring properties ofthe diaphragm 40 can be varied by means of the shaping of the corrugatedregions. Instead of the crimping on the collar 36 of the base body 24, asoldered or welded connection of the periphery of the diaphragm 40 tothe collar 36 can be made.

The exemplary embodiment of a pressure control valve of FIG. 12 isessentially equivalent to the pressure control valve of FIG. 9, exceptto reduce the compression force of the returning fuel on the diaphragm40, a corrugated return tube 66 is mounted tightly onto a mountingshoulder 65 of the valve seat body 43, on its side remote from the valveseat face 44.

The flexible return tube 66 may be made of rubber, plastic, thin metalor some other material, and it extends through the restoring spring 53and a guide opening 67 in the cap bottom 52, on the inside of which thereturn tube 66 can rest with radially extending stops 68. In that case,as shown in FIGS. 13 and 14, a connection hose 71 can be slipped tightlyonto a tube end 70 protruding from the cap 38; as FIGS. 1-6 show, thishose leads back in the form of a return line 14 to the fuel tank 1 orthe tank insert unit 2. This embodiment with the return tube isespecially advantageous whenever the returned fuel is supplied to thejet pump 3 in the fuel tank 1, because as a result the effects ofpressure fluctuations in the fuel on the pressure control valve can bekept especially slight, since these pressure fluctuations act only onthe small cross section of the valve seat body 43, rather than on thesubstantially larger cross section of the diaphragm 40.

FIG. 13 shows merely the upper portion of the cap 38, which has atubular neck 72, forming the guide opening 67, that protrudes out of thecap. The end 70 of the return tube 66 terminates, sealed off, in thetube neck 72. The connection hose 71 is slipped over the tube neck 72.In FIG. 14, unlike the above exemplary embodiments of FIGS. 12 and 13,the return tube 66 is embodied not as a corrugated tube but rather as asmooth tube, which protrudes through the guide opening 67 in the cap 38with slight play, or in other words can slide in the guide opening 67.

The exemplary embodiment of FIG. 15, which shows only the upper portionof the cap 38, differs from the exemplary embodiment of FIG. 14 merelyin that the tube end 70 protruding out of the cap 38 is provided with aclosure 73 and that in the cylindrical wall of the return tube 66outside the cap a jet nozzle 74 is provided, by way of whose jet conduit75 the returning fuel is introduced directly into the jet pump 3. Thejet nozzle 74 is thus part of the jet pump in the fuel tank 1. Inprinciple, however, combinations of the exemplary embodiments describedabove are also possible, for instance with respect to how the filter isfastened, how the closure element is formed, and so forth.

In the exemplary embodiment of FIG. 16, a resilient diaphragm 40 of thinmetal is fastened by its periphery in the base body 24, by means of thecollar 36 and crimped edge 39 with the interposition of a seal 63, andis bent in corrugated fashion in such a way that it also, simultaneouslyacting as a restoring spring, exerts a spring force on the valve seatbody 43 in the direction of the valve closing body 30. The valve seatbody 43 extends through an aperture 42 in the middle region of thediaphragm 40 and is likewise tightly secured, optionally with theinterposition of a sealing disk 76, by means of a deformation 49 ontothe side of the diaphragm 40 remote from the valve closing body 30. Thevalve seat face 44 is embodied conically or spherically In FIGS. 16-19,the retaining tongues 28 do not surround the valve closing body,embodied for instance as a ball, above its center point. In theexemplary embodiments of FIGS. 16-19 as well, however, the retainingtongues 28 may be embodied as long enough that as in the above FIGS.7-14 they surround the ball above its middle point. These longerretaining tongues 28 are shown in dashed lines as an example in FIG. 16.The valve closing body 30 is rotatably supported between the retainingtongues 28. By pressing in the bottom 25 of the base body 24 in thecentral bearing region 62 between the retaining tongues 28, the forceexerted by the metal diaphragm 40 and thus the fuel pressure to becontrolled can be varied. In this exemplary embodiment, no independentrestoring spring and thus no spring plate on the diaphragm are needed.

In a departure from the exemplary embodiment of FIG. 16, in theexemplary embodiment of FIG. 17 the diaphragm 40, which may for instancebe of plastic instead of metal, is equipped with at most a very slightspring property. Acting as the restoring spring 53 is a tension spring,which is embodied as an approximately heart-shaped leaf spring and issupported with a transverse region 78 outside the base body 24 on thebottom 25 thereof and which with arms 79 engages the valve seat body 43,in order to pull the valve seat body 43 together with the diaphragm 40in the direction of the valve closing body 30. The arms 79 in theprocess extend through the inlet openings 35 in the bottom 25.

In the exemplary embodiment of FIG. 18 as well, the restoring spring 53acts as a tension spring upon the valve seat body 43 and urges thediaphragm 40 in the direction of the valve closing body 30 and isembodied as an approximately heart-shaped leaf spring. Unlike theexemplary embodiment of FIG. 17, however, the transverse region 78 isfastened together with the diaphragm 40 to the valve seat body 43, andthe arms 79 extend through the inlet openings 35 to the outside and aresupported on the bottom 25 of the base body 24.

FIG. 19 shows an exemplary embodiment of a pressure control valve 13that as in FIG. 11 or FIG. 16 has a diaphragm 40 embodied resiliently ofmetal that at the same time, acting as a restoring spring, rests with aspring force on the valve closing body 30, in the closed state of thepressure control valve as in FIG. 11. The diaphragm 40, in its middleregion, forms a valve seat face 44 and a return conduit 44, beginningthere, to the return side 47. For forming the valve seat face 44, thediaphragm 40 is bent tapering upward conically or spherically toward themiddle and toward the return conduit 54, so as to rest in the manner ofa nozzle on the circumference of the ball-like valve closing body 30.

In FIG. 20, a pressure control valve 13 is shown whose base body 24 isembodied as a cup-shaped plastic body with a bottom 25. Inlet openings35 are provided in the bottom 25, and in the middle region of the bottoma valve closing body 30 is formed in raised fashion as an integralcomponent; this body has a flat sealing face 34 and protrudes into theinterior of the base body 24. At a collar 36 of the base body 24, theperiphery of the diaphragm 40 is fastened either by a fastening ring 80of plastic, as shown on the right-hand side of FIG. 20, or by a U-shapedclamping ring 81 of metal, as shown as a variant on the left-hand sideof FIG. 20. The plastic fastening ring 80 is preferably joined byultrasound welding to the collar 36 of the base body 24. In the middleregion of the diaphragm 40, the valve seat body 43 is inserted throughthe aperture 42 and joined by means of the deformation 49 to thediaphragm 40, with the interposition of the spring plate 48. Thelikewise flat valve seat face 44 and the valve seat body 43 cooperateswith the flat sealing face 34 of the valve closing body 30, which isformed in one piece with the base body 24. A pin 82 which has a smallercross section than the return conduit 54 in the valve seat body 43 issecured to and protrudes through the valve closing body 30. The end ofthe pin 82 remote from the valve closing body 30 is provided with a malethread onto which a screw 83 is screwed, on which screw a counterpartbearing disk 84 is supported. The restoring spring 53, embodied as acompression spring, rests on both the counterpart bearing disk 84 andthe opposed spring plate 48 and may be embodied cylindrically, as shownon the left-hand side or conically, as shown on the right-hand side. Thesecuring of the diaphragm to the metal clamping ring 81 is done by meansof the clamping force exerted on the diaphragm 40 by the clamping ring81 in the direction of the collar 36.

FIG. 21 shows a pressure control valve 13 whose cup-shaped base body 24,which has a low axial height, is disposed on a tubular unit 86 of thefuel supply system, for instance a fuel filter. The periphery of theresilient diaphragm 40 of rubber, coated cloth, plastic or metal restson a collar 36 of the base body 24 and is secured to it with a clampingbody 87 joined to the collar 36. A sleevelike valve closing body 30 issecured in the middle region of the bottom 25 of the base body 24; itsannular end face toward the diaphragm 40 forms a flat sealing face 34,and its other end face is located outside the base body 24 and is closedby a sleeve bottom 88. A valve seat body 43 that forms a flat valve seatface 44 is joined to the diaphragm, in that the valve seat body, betweenit and a diaphragm plate 89 disposed on the return side 47 of thediaphragm fastens the middle region of the diaphragm around the aperture42. Beginning at the valve seat face 44, the return conduit 54 extendsthrough the valve seat body 43 and the diaphragm plate 49. The sleevebottom 88 is engaged by one end of the restoring spring 53, in the formof a tension spring extending through the valve closing body 30 and thereturn conduit 54, whose other end is secured to a spring bracket 90that rests on the diaphragm plate 89. The force of the restoring spring53 may be brought to bear for instance by bending the spring bracket 90,which by way of example may be cross-shaped or triangular. Anotheroption for varying the force of the restoring spring 53 is shown in FIG.22, in which a bottom sleeve 91 is supported displaceably or rotatablyin or on the valve closing body 30, and is engaged by one end of therestoring spring 53. Once the spring force of the restoring spring 53has been adjusted, the sleevelike valve closing body 30 and the bottomsleeve 91 are joined together nonpositively or positively. A furtheroption for adjusting the restoring force on the diaphragm 40, besidesthe restoring spring 53, is suggested in FIG. 21 by the additionalspring 92 shown in dashed lines, which is embodied as a leaf spring andone end of which is secured to the base body 24, while the other endengages the diaphragm plate 89. Bending the additional spring 92, inaddition to the force of the restoring spring 53, makes it possible toadjust the desired restoring force on the diaphragm 40.

In the exemplary embodiment of FIG. 23, a pressure control valve 13 madesubstantially from plastic is disposed in an upper part 18, for instancea fuel filter or a holder body, in the fuel tank. The pressure controlvalve 13 has a plastic base body 24, whose wall defines an interior 94that is stepped in both axial directions. A collar 36 on which thediaphragm 40 rests with its periphery is formed on the base body 24.Remote from the collar 36, the base body 24 has a bearing portion 95 forsupporting the valve closing body 30. To that end, the bearing portion95 has an annular bearing face 96 that tapers conically toward thecenter line 93 and whose smallest diameter is smaller than the diameterof the ball-like valve closing body 30. The bearing face 96 is adjoined,in the direction toward the collar 36, by retaining lugs 97, whichextend axially to beyond the middle of the ball-like valve closing body30 and radially have a slight play with the surface of the valve closingbody 30, so that the valve closing body can rotate-between the retaininglugs 97. The retaining lugs 97 may also be located on an encompassingcontinuous retaining ring having the same cross section and theretaining lugs. To make it easier for the ball-like valve closing body30 to snap into the bearing portion 95 when the valve closing body 30 isinstalled, axially extending longitudinal slits 98 may be providedbetween the individual retaining lugs 97 in the wall of the base body24, the slits being open toward the interior 94. A cup-spring-likecocking spring 31 rests with its circumference on a collar 99 of thebearing portion 95, the collar being is remote from the valve closingbody 30, and is fastened firmly by means of a cap 100 that is joined tothe bearing portion 95, for instance by ultrasound welding. The cockingspring 31 is embodied as soft, and it urges the valve closing body 30toward the retaining lugs 97. As shown in FIG. 25, the circumference ofthe cocking spring 31 can also, by deformation of the plastic materialon the collar 99 by ultrasound welding, be fastened directly in thebearing portion 95. The diaphragm 40 resting on the collar 36 of thebase body 24 is fastened on the collar 36 by means of a tubularintermediate part 102 of plastic, which is joined to the collar 36 byultrasound welding. A cup-shaped cap part 103 of plastic can be insertedinto the intermediate part 102 or onto the intermediate part 102, and itis engaged by one end of the restoring spring 53 embodied as acompression spring. By means of an axial motion of the cap part 103relative to the intermediate part 102, the force of the restoring spring53 can be varied. Once the spring force adjustment has been completed,the intermediate part 102 and the cap part 103 are fixed to one another.Outflow openings 51 are provided in the cap part. In the middle regionof the diaphragm 40, extending through the aperture 42 of the diaphragm40, a plastic valve seat body 43 is secured, which rests with its valveseat face 44 on the sealing face 34 of the valve closing body 30 and hasthe return conduit 54. The fastening of the diaphragm 40 to the valveseat body 43 can be done by means of a fastening disk 104, which is madeof plastic and is joined to the valve seat body 43 by ultrasoundwelding. In a variant, shown in FIG. 24, of the pressure control valve14 of FIG. 23, the diaphragm 40 is fastened in its middle regiondirectly into the valve seat body 43, which has been deformed byultrasound welding. The pressure control valve 13 is retained in theupper part 18 by means of a metal toothed ring disk 105 engaging thecollar 36.

In the exemplary embodiment shown in FIG. 26 of a pressure control valve13, the valve seat body 43 is joined to the diaphragm 40 and coaxiallyto one another in the flow direction has first a guide conduit 106, thenthe valve seat face 44, and then the return conduit 54 toward the returnside 47. The valve closing body 30 embodied as a ball is guided axiallyin the guide conduit 106. Axial grooves 108 open toward the guideconduit 106 extend in the valve seat body 43 as far as the valve seatface 44 and enable an easy flow around the valve closing body 30 in theguide conduit. Located on the return side 47 of the diaphragm 40 is aspring plate 48, with which the valve seat body 43 extending through thediaphragm 40 in the aperture 42 is joined by means of a deformation 49.A leaf-spring-like closing spring 109 extends transversely through theguide conduit 106 and is fastened by its edges in the valve seat body43, while its middle region engages the valve closing body 30 and exertsa spring force upon it in the direction of the valve seat face 44, inorder to keep the valve closing body in the sealing position on thevalve seat face 44. The closing spring 109 is embodied as a soft spring.The diaphragm 40 is fastened at its periphery, together with thecircumference of a cup-shaped cap 38 resting on the return side 47, inthe base body 24 by means of the crimped edge 39. The base body 24itself has a retaining shoulder 110 adjoining the collar 38 in theradially inward direction; this shoulder is spaced apart from the collar36 only slightly and extends horizontally merely to the valve seat body43. If the fuel supply system is not in operation, then the diaphragm 40in its position of repose rests on the retaining shoulder 110, withoutany undesired and impermissible deformation. Supported on the cup-shapedcap 38 is the restoring spring 53, which for instance is embodied as aleaf-spring-like spiral spring and which likewise engages the springplate 48. A stop lug 111 is formed out of the cap 38, extending into theinterior of the cap and pointing in aligned fashion at the valve closingbody 38. If the pressure of the fuel in the fuel line 5 is lower thanthe fuel pressure to be controlled, or if the fuel supply system is notin operation, then an axial spacing exists between the valve closingbody 30 and the stop body 111 of the cap 38, the stop body being formedout in the form of a half ring, and the valve closing body 30 restssealingly on the valve seat face 44. If the fuel pressure on thepressure control side 45 of the diaphragm rises above the fuel pressureto be controlled, then the diaphragm is made to bend in the direction ofthe cap 38, and the valve closing body 38 comes to rest on the stop body111 and is prevented by it from any further axial motion with thediaphragm 40, so that the valve closing body 30 lifts from the valveseat face 44, and fuel can flow out to the return side 47 via the valveseat face 44 and the return conduit 54, and the fuel pressure on thepressure control side 45 is kept at the predetermined constant value.The pressure control valve 13, inserted into some unit of the fuelsupply system, such as a fuel filter 17 in the fuel tank 1 or in thetank insert unit 2, rests there with the collar 38 in sealed fashion ona protrusion 112 and is fixed on this protrusion by a toothed ring disk105 engaging the crimped edge 39.

The exemplary embodiment shown in FIG. 27 differs from the pressurecontrol valve of FIG. 26 only in that the cap 38 in its bottom 52 has acentral threaded portion 113, which extends for instance into theinterior of the cap 38 and into which a stop body 111 embodied as ascrew and aligned with the valve closing body 30 is inserted. If thepressure of the fuel on the pressure control side 45 of the diaphragmrises above the predetermined pressure, then the valve closing bodyrests on the stop body 111 and is lifted from the valve seat face 44, sothat fuel can flow to the return side 47. In the exemplary embodiment ofFIG. 27, unlike the exemplary embodiment of FIG. 26, the restoringspring 53 is embodied as a compression spring. In the exemplaryembodiments of FIGS. 26 and 27, the force of the restoring spring 53 canbe varied in each case by bending of the cap bottom 52.

The foregoing relates to preferred exemplary embodiments of theinvention, it being understood that other variants and embodimentsthereof are possible within the spirit and scope of the invention, thelatter being defined by the appended claims.

What is claimed is:
 1. A pressure control valve for fuel supply systemsof internal combustion engines, having a base body embodied as acup-shaped sheet-metal body with a bottom (25), and retaining tongues(28) are formed out of the bottom (25) and bent into an interior of thebase body (24), these tongues supporting the valve closing body (30);comprising a resilient diaphragm fastened by a periphery of saidresilient diaphragm to said base body, the diaphragm having a pressurecontrol side acted upon by the fuel on said pressure control side to becontrolled and a return side opposite the pressure control side; a valveseat face located in a middle region of the diaphragm; a valve closingbody that cooperates with the valve seat face; and having a spring forcethat acts in the valve closing direction, the diaphragm (40) isdeflectable relative to said periphery in said middle region with thevalve seat face (44), and when the valve seat face (44) is lifted fromthe valve closing body (30), fuel flows via the valve seat face (44)through the diaphragm (40) from the pressure control side (15) towardthe return side (47) of the diaphragm (40), and the valve closing body(30) is embodied as a ball and is rotatably supported in a cage formwhich is built up as an integral part of the base body (24) in contactwith the valve closing body (30).
 2. The pressure control valve of claim1, in which the ball-like valve closing body (30) has a flat sealingface (34) toward the valve seat face (44).
 3. The pressure control valveof claim 2, in which a cocking spring (31), which urges the valveclosing body (30) toward the valve seat face (44), is disposed betweenthe bottom (25) of the base body (24) and the valve closing body (30).4. The pressure control valve of claim 2, in which a valve seat body(43) having the valve seat face (44) and a return conduit (54) leadingfrom it to the return side (47) is connected to the diaphragm (40). 5.The pressure control valve of claim 2, in which the valve seat face (4)is embodied as flat, conical or spherical.
 6. The pressure control valveof claim 1, in which the diaphragm (40) is acted upon on its return side(44) by a restoring spring (53) acting toward the valve closing body(30).
 7. The pressure control valve of claim 6, in which the restoringspring (53) is embodied as a compression spring and rests with its endremote from the diaphragm (40) on a cap (38) that is joined by means ofa crimped edge (39) to the base body (24), and the diaphragm (40) isfastened between the cap (38) and the base body (24).
 8. The pressurecontrol valve of claim 6, in which inlet openings (35) are embodied inthe bottom (25) of the base body (24), and a filter (59, 60) coveringthe inlet openings (35) is disposed on the bottom (25).
 9. The pressurecontrol valve of claim 8, in which the filter (59, 60) is retained onthe base body (24) by means of a detent connection (57, 58).
 10. Thepressure control valve of claim 1, in which to adjust the spring forceof the restoring spring (53), the base body (24) is deformable in thedirection toward the valve seat face (44).
 11. The pressure controlvalve of claim 10, in which the restoring spring (53) is embodied as aleaf spring.
 12. The pressure control valve of claim 4, in which thediaphragm (40) is embodied resiliently of metal and has an opening in amiddle region which directly forms the valve seat face (44) and a returnconduit (54) that leads to the return side (47).
 13. The pressurecontrol valve of claim 8, in which a thin-walled return tube (66) isjoined to the valve seat body (43) in sealed fashion on the return side(47) of the diaphragm (40).
 14. The pressure control valve of claim 2,in which the thin-walled return tube (66) communicates, on the intakeside of a fuel pump (4), with a jet pump (3) disposed in the fuel tank(1).
 15. The pressure control valve of claim 2, in which the diaphragm(40) is embodied resiliently of metal.
 16. The pressure control valve ofclaim 6, in which toward the valve closing body (30), a leaf-spring-liketension spring acting as a restoring spring (53), which is supported onthe base body (24), engages the valve seat body (43).
 17. The pressurecontrol valve of claim 16, in which the diaphragm (40) is embodied asflat in its middle portion forming the valve seat face (44).
 18. Thepressure control valve of claim 6, in which the diaphragm (40) is bentconically or spherically in its middle region forming the valve seatface (44) tapering toward the return conduit (54).
 19. A pressurecontrol valve for fuel supply systems of internal combustion engines,having a base body; comprising a resilient diaphragm fastened by aperiphery of said resilient diaphragm to said base body, the diaphragmhaving a pressure control side acted upon by the fuel on said pressurecontrol side to be controlled and a return side opposite the pressurecontrol side; a valve seat face located in the middle region of thediaphragm; a valve closing body that cooperates with the valve seatface; and having a spring force that acts in the valve closingdirection, the diaphragm (40) is deflectable relative to said peripheryin said middle region with the valve seat face (44), and when the valveseat face (44) is lifted from the valve closing body (30), fuel flowsvia the valve seat face (44) through the diaphragm (40) from thepressure control side (15) toward the return side (47) of the diaphragm(40), and the base body (24) is embodied as a cup-shaped plastic bodywith a bottom (25), and the valve closing body (30) provided with a flatsealing face (34) is an integral part of the bottom (25), and a valveseat body (43) that has a flat valve seat face (44) and a return conduit(54) leads from the flat valve seat body to the return side (47) isjoined to the diaphragm (40), a pin (82) is provided on the valveclosing body (30), said pin (82) protrudes through the return conduit(54) of the valve seat body (43) and on a free end of said pin bears acounterpart bearing disk (84) for a restoring spring (53) that acts onthe diaphragm (40).
 20. The pressure control valve of claim 14, in whichthe free end of the pin (82) is provided with a male thread onto which anut (83) provided with a female thread is screwed, on said nut, thecounterpart bearing disk (84) rests and by means of said nut the forceof the restoring spring (53) on the diaphragm (40) can be adjusted. 21.A pressure control valve for fuel supply systems of internal combustionengines, having a base body; comprising a resilient diaphragm fastenedby a periphery of said resilient diaphragm to said base body, thediaphragm having a pressure control side acted upon by the fuel on saidpressure control side to be controlled and a return side opposite thepressure control side; a valve seat face located in the middle region ofthe diaphragm; a valve closing body that cooperates with the valve seatface; and having a spring force that acts in the valve closingdirection, the diaphragm (40) is deflectable relative to said peripheryin said middle region with the valve seat face (44), and when the valveseat face (44) is lifted from the valve closing body (30), fuel flowsvia the valve seat face (44) through the diaphragm (40) from thepressure control side (15) toward the return side (47) of the diaphragm(40), and the base body (24) is embodied as cup-shaped, with a bottom(25) on which a sleevelike valve closing body (30) is secured, whoseannular end face toward the diaphragm (40) forms a flat sealing face(34) and whose other end face is closed off by a sleeve bottom (88), anda valve seat body (43) that has a flat valve seat face (44) and a returnconduit (54) leading from it to the return side (47) is joined to thediaphragm (40), and a restoring spring (53) in the form of a tensionspring engages the sleeve bottom (88) and the valve seat body (43). 22.A pressure control valve for fuel supply systems of internal combustionengines, having a base body; comprising a resilient diaphragm fastenedby a periphery of said resilient diaphragm to said base body, thediaphragm having a pressure control side acted upon by the fuel on saidpressure control side to be controlled and a return side opposite thepressure control side; a valve seat face located in the middle region ofthe diaphragm; a valve closing body that cooperates with the valve seatface; and having a spring force that acts in the valve closingdirection, the diaphragm (40) is deflectable relative to said peripheryin said middle region with the valve seat face (44), and when the valveseat face (44) is lifted from the valve closing body (30), fuel flowsvia the valve seat face (44) through the diaphragm (40) from thepressure control side (15) toward the return side (47) of the diaphragm(40), and a valve seat body (43) having the valve seat face (44) and areturn conduit (54) leading from said return conduit to the return side(47) is joined to the diaphragm (40), and the valve closing body (30),embodied as a ball, is disposed in the valve seat body (43) in a guideconduit (106) located upstream of the valve seat face (44), and that onthe return side (47) of the diaphragm (40) a cap (38) is joined to thebase body (24), on which cap a stop body (111) is disposed pointing tothe valve closing body (30).
 23. A pressure control valve for fuelsupply systems of internal combustion engines, having a base body;comprising a resilient diaphragm fastened by a periphery of saidresilient diaphragm to said base body, the diaphragm having a pressurecontrol side acted upon by the fuel on said pressure control side to becontrolled and a return side opposite the pressure control side; a valveseat face located in the middle region of the diaphragm; a valve bodythat cooperates with the valve seat face; and having a spring force thatacts in the valve closing direction, the diaphragm (40) is deflectablerelative to said periphery in said middle region with the valve seatface (44), and when the valve seat face (44) is lifted from the valveclosing body (30), fuel flows via the valve seat face (44) through thediaphragm (40) from the pressure control side (15) toward the returnside (47) of the diaphragm (40), and the valve closing body (30) isembodied as a ball and is rotatably supported in a cage form which isbuilt up as an integral part of the base body (24) in contact with thevalve closing body (30), the base body (24) is cup-shaped, with a bottom(25) in which the inlet openings (35) are provided around a centralbearing region (62), wherein retaining tongues (28) of a cup-shapedretaining sleeve (64) protrude through the inlet openings (35) into theinterior of the base body (24) and support the valve closing body (30)on the central bearing region (62).
 24. A pressure control valve forfuel supply systems of internal combustion engines, having a base body;comprising a resilient diaphragm fastened by a periphery of saidresilient diaphragm to said base body, the diaphragm having a pressurecontrol side acted upon by the fuel on said pressure control side to becontrolled and a return side opposite the pressure control side; a valveseat face located in the middle region of the diaphragm; a valve bodythat cooperates with the valve seat face; and having a spring force thatacts in the valve closing direction, the diaphragm (40) is deflectablerelative to said periphery in said middle region with the valve seatface (44), and when the valve seat face (44) is lifted from the valveclosing body (30), fuel flows via the valve seat face (44) through thediaphragm (40) from the pressure control side (15) toward the returnside (47) of the diaphragm (40), and the valve closing body (30) isembodied as a ball and is rotatably supported in a cage form which isbuilt up as an integral part of the base body (24) in contact with thevalve closing body (30), the base body (24) is embodied of plastic andhas a collar (36), on which the diaphragm (40) rests by acircumferential edge, and remote from the collar (36) the base body (24)has a bearing portion (95) which forms the cage form for supporting thevalve closing body
 30. 25. The pressure control valve of claim 1, inwhich the bearing portion (95) has elastic retaining lugs, (97), whichdefine a circular cross section of shorter radius than the radius of thevalve closing body (30).
 26. The pressure control valve of claim 2, inwhich a cocking spring (31) engages the side of the valve closing body(30) remote from the diaphragm (40) and urges the valve closing body(30) in the direction toward the retaining lugs (97).
 27. The pressurecontrol valve of claim 2, in which the diaphragm (40) is fastened to thecollar (36) of the base body (24) by means of a tubular intermediatepart (102) of plastic, and remote from the base body (24) a cup-shapedcap part (103) of plastic engages the intermediate part (102), the cappart being axially movable relative to and fixable on the intermediatepart (102).
 28. The pressure control valve of claim 27, in which in themiddle region with the diaphragm (40) a valve seat body (43) of plasticis joined to the diaphragm (40), and the valve seat body (43) has avalve seat face (44) and a return conduit (54) leading from it to thereturn side (47).
 29. The pressure control valve of claim 28, in which arestoring spring (53) embodied as a compression spring is disposedbetween the cap part (103) and the valve seat body (43).
 30. Thepressure control valve of claim 22, in which a soft closing spring (109)is disposed in the valve seat body (43), engaging the side of the valveclosing body (30) remote from the valve seat face (44) and urging it inthe direction toward the valve seat face (44).